Cassette Persistence

By default, cassettes will be persisted to the file system. However, you
can easily configure VCR to persist the cassettes to a database, a key-value
store, or anywhere you like.

To use something besides the file system, you must provide an object
that provides a hash-like interface:

persister[name] should return the content previously persisted for the
given cassette name.

persister[name] = content should persist the content for the
given cassette name.

Register this object with VCR, and then you can configure all cassettes
to use it (using the default_cassette_options) or just some cassettes
to use it (by passing it as an option to individual cassettes).